Take a regular black ballcap, add a gizmo over the bill that looks like a miniature toilet paper dispenser and you have the Cool Smile Thermoelectric Cooling Cap. It costs $55 and you can get one or several (summer family fun?) today at AC Gears.
It may look clunky, but that thing on the hat is actually designed to keep your body temp down when you're sweating bullets. It's called a Peltier device, named after French physicist Jean-Charles-Athanase Peltier. In 1834 Peltier realized that sending an electric current through a circuit where two different conductors or semiconductors are linked can produce either heat or cold. Which one depends entirely on the direction the current is flowing.
Attached to a hat, the Peltier effect uses thermoelectricity to pull heat away from your head using an AA battery. In less than five minutes, the temperature can drop as low as 60 degrees and be maintained for one or two hours. Would you laugh in the face of fashion faux pas to rock this heat-destroying thermoelectric hat?